Rubber Band
by WaiiKitsune
Summary: When stretched past a limit, rubber bands snap, and Tsuna thinks he knows how that feels now.


**Title:** Rubber Band

 **Summary:** When stretched past a limit, rubber bands snap, and Tsuna thinks he knows how that feels now.

 **Disclaimer:** Katekyo Hitman Reborn! belongs to Akira Amano

 **Pairing:** None-ish

 **Warning:** Set post-canon, possible OoC-ness.

* * *

 **Rubber Band**

* * *

When Reborn finally returned to the Vongola estate at nearly 2a.m. in the morning, he was not expecting to find Tsuna awake, much less _waiting for him_. (The Vongola Decimo's sleep schedule was, after all, one of the few things in his life that was still somewhat normal, and he treasured it _deeply_.)

"Tsuna?"

The room was dark; all the lights in the office were turned off except for the desk lamp. The remaining illumination came from the balcony on the right of the room, where it is decidedly _not_ behind the large mahogany desk. At his desk, Sawada Tsunayoshi showed no signs of having heard the hitman… or so he would have, if Tsuna hadn't paused momentarily in the signing of the document before him. That did not stop the brunet from ignoring Reborn, however, for the duration of the signing, where, under normal circumstances, the Don Vongola would have already made a noise of acknowledgement.

Reborn didn't know what was wrong, but he knew that something _had_ happen, and that Tsuna was very, _very_ angry.

Now, Sawada Tsunayoshi had a level of patience that is unheard of in the mafia; very few things felt the full brute of the Vongola Decimo's pure, unadulterated anger, but right now, Reborn had a distinct feeling _he_ was one of them (for reasons still unfathomed). The hitman had seen what was the end result of those suffering said wrath, and the fact that Reborn still didn't know what he had done to be the at the receiving end was, frankly, a tad on the terrifying side (as much as he hated to admit it).

The knock of a pen against wood when Tsuna finally put down the instrument was loud in the silence of the room, and

Lbrought Reborn's attention back from his wandering thoughts. Quietly, he watched as Tsuna tidied the stacks of paperwork on his desk before the brunet stepped out from behind and crossed the room in quick strides.

"Follow me."

The words spoken in a tone that was more than a request but less than a command had Reborn turning to follow his former student out of the office. At this time, the Vongola estate was fairly quiet, with only the night security shift. Tsuna walked briskly and silently in the dimmed estate, without ever once turning to address the man following him.

Reborn wasn't very surprised when Tsuna lead them to Training Room 1, the largest and most enforced training room. Still yet to speak any further, the brunet continued until he reached the middle of the training room, while Reborn stood across from him, carefully watching the Don Vongola.

Tsuna's entire stance was taunt—with tension or anger, Reborn could not tell. Though his face remained calm, Reborn could see the faint, tell-tale sign of gold seeping into Tsuna's eyes. The brunet's hands remained by his side, clenched but not overly tight, and more importantly, Tsuna's dormant mittens were very obviously peeking out of his pockets.

"What's going on?" Reborn finally asked, very careful to keep his tone even and free of the slightest hint of accusation.

Tsuna stared back at him, his breathing deliberately deep and even. Then, in a voice so quiet, Reborn would have missed if not for the dead silence of the training room, "When were you going to tell me?"

"…Tell you what, Tsuna?" Reborn frowned, genuine confusion showing on his face.

"...I see." Tsuna murmured. "So that's your answer…"

In a speed that was surely a new record, Tsuna had lunged forward, throwing a punch that Reborn barely managed to bring up his arms to block in time and sending the hitman flying across the large training room. Reborn hit the wall with a loud smack that reverberated through the enclosed space. Instantly, he threw himself to the side, dropping into a roll, as Tsuna continued in his assault. Reborn dodged again as the brunet flew at him again, refusing to draw his weapon against his former student. Though Tsuna rarely managed to beat Reborn during their regular spars, anger and adrenaline were both excellent motivators, and the hitman was actually finding difficulty in successfully avoiding all the attacks.

"Tsuna! What's going on?!" Reborn demanded.

"You were never going to tell me!" Tsuna snarled in accusation.

The Dying Will Flames burned a disturbingly dark amber on his forehead, while the flames that flared from Tsuna's gloves were so wild and uncontrolled, it was almost burnt orange in colour. Fully in Hyper Dying Will mode, Tsuna's eyes were the colour of molten gold, and every bit of his rage mirrored on the Sky Lion standing on his shoulder.

Reborn knew he had to stop Tsuna somehow; retaliation wasn't an option, yet he couldn't dodge forever and let the brunet be. The Sky flames were only getting darker by the minute—a clear sign that Tsuna was losing himself.

Thankfully for the hitman, whether it was because the adrenaline was starting to wear off, or something else altogether, Tsuna was slowing down just enough for Reborn to lunge at at first opportunity. Reborn tackled Tsuna to the ground, grunting as he used all his strength to pin the trashing and snarling brunet down.

" _Don't touch me!"_ Tsuna snapped. Still on his shoulder, Natsu let out a roar of Sky Flames, the close proximity to it sending Reborn flying into the opposite wall again.

This time, when Tsuna attacked again, his movement no longer held any finesse.

Reborn let out a string of multilingual expletives in his head as he was forced into another round of cat-and-mouse. Tsuna attacking without any care or tactics meant that he was more reckless, bringing about more openings but also unpredictability. Reborn couldn't risk attempting to pin Tsuna down either; not with Natsu still present and reflecting its master's immense rage. And while Reborn knew help was on its way—all training rooms were monitored at all times, and whoever was on duty would have alerted Gokudera by now—for once, the hitman wasn't confident if he could last until the Guardian arrived.

"What the— _Jyuudaime_?!"

"Tsuna!"

Reborn didn't even have the luxury of sparing the two Guardians a glance; as it is, he narrowly managed to avoid the kick aimed at his chest. Distantly, the hitman heard Gokudera barking at someone—Lambo?—to get the other Guardians in the estate, while Yamamoto rushed forward, Kojirou already materialising and raining down Rain flames as it circled the air above the duo.

"Tsuna!" Yamamoto called again, but the brunet paid him no heed. "Tsuna, what's wrong? Tsuna!"

"I don't think Jyuudaime is hearing anything right now, Yamamoto." Gokudera pointed out, hanging back as he was reluctant to bring out his Sistema C.A.I. against his beloved boss. "Jyuudaime's flames are too intense. He's burning through your Rain flames too quickly; can you up the output?"

"I'm not sure that'll help." Yamamoto admitted as he observed the one-sided fight. "I'm not sure what's going on, but Tsuna is very angry at Reborn." Casting his fellow Gurdian a look, the swordsman continued, "I'm going to stop Tsuna directly. You get Reborn away from here."

Gokudera glanced back at the ongoing assault; despite the large amount of Rain flames pouring down on Tsuna, the light blue flames were being burnt away almost instantly, and Tsuna showed no signs of being affected at all. Gokudera didn't know what had gotten his beloved boss into such a stage of rage, but the fact that he was, meant that the issue involved was too important to him. Every scream and snarl from Tsuna tore at the Guardians' hearts, and they were barely able to look.

"…Be careful, Baseball Idiot." Gokudera said quietly. "The others should be here soon."

Yamamoto grinned wearily, and rushed off. As he tackled at Tsuna, he simultaneously summoned Jirou, swiftly instructing the Rain Akita to separate Natsu from its master for as long as possible. With the Sky Lion out of the way, it was slightly easier for Yamamoto to pin Tsuna down, and while the brunet continued struggling, he had already exhausted a good part of his stamina earlier. Gokudera took the chance to approach Reborn, helping the hitman up and across to the other side of the room just as the training room doors opened again. The split second of distraction was enough for Tsuna to throw Yamamoto off, flames flaring from his gloves as he flew towards the other end of the training room, only to get caught up momentarily by lotus vines.

"Explain!" Hibari barked out as he moved to intercept Tsuna.

"Tsuna's angry at Reborn, and no one knows why." Yamamoto replied, getting off the ground with a wince. "My Rain flames aren't working much on him."

"Well, whatever the Arcobaleno did, I'm impressed." Mukuro snorted as he effortlessly summoned more lotus vines to replace the ones Tsuna burnt through. "Oh, put your little hedgehog into it, Skylark. I'm not endlessly regenerating my lotus vines for you."

"What are you—" Reborn started, but Gokudera yanked on his arm harshly and pulled him back.

"Reborn-san," Gokudera started. "I have not, in all honestly, seen Jyuudaime this pissed off since the alternate future, when the Sky Arcobaleno had sacrificed herself to save us all. The fact that Jyuudaime currently requires Yamamoto, Hibari, and Mukuro _willingly_ and actively working together to contain speaks a lot for itself." He tore his sight from the scene to glare at the Sun Arcobaleno with dark emerald orbs. "With all due respect, Reborn-san, get the fuck out."

As much as Reborn hated to admit it—and the amount of moments he had felt that in the last hour is reaching ridiculous levels—he knew Gokudera was right. As long as he remained in the room, Tsuna would not calm down, and the only way to stop the brunet was to utterly exhaust him, but to do that without injuring him was near-impossible. There was nothing Reborn could do but to leave and let Tsuna calm down.

And as Reborn turned to leave swiftly, he ignored the pain pulling at his chest as he caught the sight of the brunet being swallowed up by Roll in Needle Sphere form.

* * *

It had taken the combination of Reborn physically leaving the training room and Hibari trapping Tsuna in Roll's Needle Sphere form while Mukuro restrained him with lotus vines and Kojirou's continuous conjuring of Rain flames within for Tsuna to finally pass out. Even then, after transporting the unconscious Don Vongola to his room, Yamamoto had to continue applying Rain flames until Ryohei, who had been on his way back to the estate, returned to properly tranquillise Tsuna for the remainder of the night.

The five oldest Guardians were gathered in the adjacent seating room. Gokudera and Yamamoto, being the first to reach the training room, recounted the incident from start to end for the benefit of the confused Sun Guardian.

"It's not like Jyuudaime to attack someone without reason, and so aggressively at that." Gokudera frowned. "And said person is Reborn-san too. What could possibly have set him off like that?"

"Sawada Tsunayoshi adores the little Arcobaleno." Mukuro stated. "I highly doubt there is anything in the world that could make him angry at the Arcobaleno." His eyes twinkled in amusement and mischief then, as the illusionist continued, "Of course, we can solve this easily enough if you just let me into his mind…"

"You stay where you are." Gokudera huffed automatically.

"I might actually have an idea." Ryohei, who had been silent at this time, spoke up, slowly and hesitantly, and all four Vongola Guardians turned to him. "But if I'm right, then you'll have to call in Dr. Shamal because I won't be able to convince Tsuna."

"What do you suspect, senpai?" Yamamoto prompted.

"I think… Tsuna and Reborn might be soulmates."

* * *

"Of _all_ people, Reborn and the brat." Shamal muttered, massaging his temples. Glancing at Ryohei out of the corner of his eyes, he questioned, "How sure are you?"

"We discussed this, and we think Ryohei is probably right." Gokudera answered instead. "The timeline, at least, fits."

The mission that Reborn had just returned from was assigned to the hitman a week ago. It was two days ago when Ryohei had walked into Tsuna's office, sternly questioning why the Vongola Decimo had sent Reborn on a mission when the hitman was supposed to be recovering from the injury he had received on the previous mission. Ryohei could remember clearly the look of confusion on Tsuna's face as the brunet explained that he was completely unaware that Reborn had been injured. While it was the norm for Ryohei to report to Tsuna about the Family's injuries, the Sun Guardian explained that Reborn had insisted that he would report the injury to Tsuna himself and, though Ryohei had found the request a tad odd, he had agreed.

As it turned out, Reborn never reported the injury, nor did he include it in his post-mission report.

And, when Ryohei had answered Tsuna's enquiry about the injury, the brunet's face had completely frozen, before his usual slightly-exasperated-but-mostly-calm look had taken over, and Tsuna had promised to talk to Reborn about hiding his injuries when the hitman returned.

"He lied…"

The weak voice had all eyes in the room turning towards the bed, where a weary and almost defeated-looking Tsuna was slowly sitting up. Natsu was curled in his lap, whimpering with its ears flat on its skull. In contrast to the rage-stricken brunet they'd witnessed hours ago, Tsuna now looked completely opposite—tired, crushed and all but given up.

"Reborn lied." Tsuna repeated quietly. "Whatever existing bond the Arcobaleno had was sealed when they were cursed, but after we broke it… when their bodies physically reached the appropriate age, it would have returned—Colonnello and Lal were proof of that." His sight was downcast as the brunet subconsciously stroke Natsu's fur for comfort. "I was hardly the epitome of gracefulness. While I've gotten increasingly less clumsy by the years, my physical training conversely increased. And back then, Reborn was still in charge of my training, so he was not only around almost all the time, but he would have known and _felt_ every single one of my injuries." Finally, his head lifted, and Tsuna stared at the room with dull brown eyes.

"Reborn had known that we were soulmates for at least three years, and he kept quiet all this time." And before Shamal could stop him, he finished, "Clearly our soul bond means nothing to him."

Tsuna felt the effects of his words almost instantly. The pain that had been tugging at his chest ever since he had found out about the injury Reborn hid intensified. The pull grew tighter and tighter still, much like how a rubber band would feel like when stretched, until finally, something within Tsuna snapped, and he screamed.

Distantly, Tsuna heard Shamal snapping at his charge—"Gokudera, go get Reborn!"—and he forced down enough the pain to choke out, " _Don't—_ "

"Sawada, your soul bond broke." Shamal stated. "You can't just—"

"Broken soul bonds aren't as uncommon as you think." Tsuna bit out. Though his chest felt like it was on fire, and he wanted desperately to claw his heart out, Tsuna persisted through the pain and continued, "And while a broken soul bond is excruciating painful, no one has ever _died_ of a broken bond."

"The pain from a broken soul bond—especially one that broke of mistrust like yours—will _never_ fade." Shamal pointed out grimly. "Are you saying you'd rather suffer the pain for the rest of your life than to fix this?"

"He lied to me for at least three years, Dr. Shamal." Tsuna snarled. " _Three years_. If this… If our soul bond meant anything to him _at all_ , he would have brought it up a long time ago. Tell me, what point is there to fix a bond that one half of said bond clearly doesn't want it?"

No one in the room could nor dared to rebut.

"I am _fine_." Tsuna gritted out. "I swear on Primo's grave; I _will_ be **fine**."

* * *

A/N: Well, I don't think this turned out as heartbreaking as I hoped it would. And I was actually planning to write a fight scene between Reborn and Tsuna, but it turned out more contemplating while dodging deadly attacks instead. I'm still decently satisfied at how this turned out though, so I hope you enjoyed reading this!

Thanks for reading as always! Happy Valentine's Day~ Ciao Ciao~


End file.
